WO2021192911A1

WO2021192911A1 - Coil spring jig, coil spring manufacturing method, and coil spring testing method

Info

Publication number: WO2021192911A1
Application number: PCT/JP2021/008610
Authority: WO
Inventors: 亀田　裕克; 鋭浩小川; 晋司笠鳥; 敦村上; 加藤　秀樹; 賢次長岡
Original assignee: 日立Astemo株式会社; 本田技研工業株式会社
Priority date: 2020-03-24
Filing date: 2021-03-05
Publication date: 2021-09-30
Also published as: TW202202754A; TWI770887B; CN115135899B; JP7379233B2; US12173767B2; CN115135899A; US20230014164A1; JP2021152376A

Abstract

A coil spring jig (10) comprises: a spring support (13) upon which one end of a coil spring (Sp) can be rested; a plurality of displacement-limiting parts (14) that extend from the spring support (13) along an axis (CL), are capable of contacting the outer circumference of the coil spring (Sp), and limit radial displacement of the coil spring (Sp); and a cap (15) that is supported by the displacement-limiting parts (14), and, together with the spring support (13), is capable of clamping the coil spring (Sp) to keep the coil spring (Sp) in a compressed state. Preferably, only the displacement-limiting parts (14) are provided between the spring support (13) and the cap (15).

Description

Coil spring jig, coil spring manufacturing method, and coil spring test method

The present invention relates to a jig for a coil spring and the like for keeping the coil spring in a compressed state.

Stress shot peening is known to perform shot peening on a coil spring that is kept in a compressed state. Residual stress can be applied to the coil spring by performing stress shot peening. As a conventional technique for keeping a coil spring in a compressed state, there is a technique disclosed in Patent Document 1.

The stress shot peening device shown in Patent Document 1 includes a lower receiving guide of a coiled spring material and a compression portion provided at a predetermined interval in the vertical direction of the lower receiving guide.

According to this device, a predetermined compressive force can be applied to the coiled spring material by displacing the compression portion downward. The coiled spring material can be shot peened.

Special Publication No. 57-1391

By the way, a coil spring having a long free length with respect to the coil center diameter is used for an elongated device such as a front fork of a two-wheeled vehicle. In order to perform stress shot peening on such a coil spring, it is conceivable to use a stress shot peening device as disclosed in Patent Document 1.

However, if stress shot peening is performed on a spring having a free length with respect to the center diameter of the coil, the spring may be deflected in the radial direction, in other words, the coil spring may bend. There is room for improvement in this regard.

An object of the present invention is to provide a jig for a coil spring or the like, which can apply residual stress to the inner peripheral surface of the coil spring while preventing the body of the coil spring from bending.

As a result of diligent studies, the present inventors have a large number of turns and an outer diameter, such as a coil spring for a suspension device of a saddle-type vehicle on which an occupant straddles, such as a two-wheeled vehicle or a three-wheeled vehicle. It was found that when shot peening (that is, stress shot peening) is performed in a state where a compressive load is applied to a coil spring having a small value, there is a risk of body bending. Furthermore, the present inventors have found that it is important to increase the fatigue strength on the inner peripheral surface side of the coil spring in order to increase the fatigue strength of the coil spring for the suspension device. Based on these findings, the present inventors have studied a technique capable of increasing the fatigue strength on the inner peripheral surface side of the coil spring and suppressing the occurrence of body bending during stress shot peening. bottom. As a result, as a countermeasure technique for suppressing the occurrence of body bending, a rod-shaped or tubular member that can contact the surface of the coil spring is arranged on the inner peripheral surface side or the outer peripheral surface side of the coil spring to form a coil. It was found that it is effective to suppress the radial displacement of the spring. Further, by arranging the rod-shaped or tubular member on the outer peripheral surface side of the coil spring, the projectile bends while maintaining a state in which the projection material easily collides with the inner peripheral surface of the coil spring when performing stress shot peening. It was found that it is possible to suppress the occurrence of. The present invention has been completed based on this finding.

The present disclosure will be described below.

According to one aspect of the present invention, from the spring support portion to the coil spring with reference to a spring support portion on which one end of the coil spring can be mounted and the coil spring supported by the spring support portion. A plurality of displacement regulating portions that extend along the axis and can contact the outer peripheral surface of the coil spring and regulate the displacement of the coil spring in the radial direction of the coil spring, and are supported by these displacement regulating portions. A coil spring jig having a lid portion capable of keeping the coil spring in a compressed state by sandwiching the coil spring together with the spring support portion is provided.

According to another aspect of the present disclosure, a spring support portion capable of mounting one end of the coil spring and having a hole extending along the axis at a position where the axis of the coil spring passes, and the spring support portion. A plurality of displacement regulating portions that extend from the axis along the axis and can abut on the outer peripheral surface of the coil spring and regulate the displacement of the coil spring in the radial direction of the coil spring, and these displacement regulating portions. By sandwiching the coil spring together with the spring support portion, the coil spring can be kept in a compressed state and the axis line passes through. A lid portion having a hole extending along the axis at a position to be formed, a claw portion provided on the lid portion and fitted to the displacement regulating portion, and a claw portion formed on the displacement regulating portion and fitted with the claw portion. It has a lid fitting portion that restricts the movement of the lid portion in the axial direction in the fitted state, and only the displacement restricting portion is provided between the spring support portion and the lid portion. A coil spring jig provided with is provided.

According to the present invention, it is possible to provide a jig for a coil spring or the like that can apply residual stress to the inner peripheral surface of the coil spring while preventing the body of the coil spring from bending.

It is a front view of the coil spring jig according to the first embodiment, and the coil spring kept in a compressed state by the coil spring jig. It is an exploded perspective view of the jig for a coil spring shown in FIG. It is a flow chart explaining the manufacturing method of the coil spring using the jig for the coil spring shown in FIG. It is a figure explaining the coil spring setting process. It is a figure explaining the compression process. It is a 5A arrow view of FIG. 4B. FIG. 5 is a diagram illustrating a state in which the lid portion shown in FIG. 5A is rotated. It is a figure explaining the shot peening process shown in FIG. It is a figure explaining the removal process. It is a figure explaining the test method of the coil spring by Example 2. FIG.

An embodiment of the present invention will be described below with reference to the attached figure. The form shown in the attached figure is an example of the present invention, and the present invention is not limited to this form.

<Example 1>
See FIG. The coil spring jig 10 (hereinafter referred to as "jig 10") is a jig capable of holding the coil spring Sp (hereinafter referred to as "spring Sp") in a compressed state. The spring Sp is held by the jig 10 in a state of being compressed by a predetermined length from the free length.

The jig 10 has a spring support portion 13 on which the lower end (one end) of the spring Sp is in contact and on which the spring Sp can be placed, and the jig 10 extends from the spring support portion 13 along the axis CL of the spring Sp. The three displacement regulating portions 14 that regulate the radial displacement of the spring Sp by being provided so as to be in contact with the outer peripheral surface, and the spring Sp are supported by these displacement regulating portions 14 together with the spring supporting portion 13. It has a lid portion 15 that can keep the spring Sp in a compressed state by sandwiching the spring Sp. In the jig 10, the three displacement regulating portions 14 are arranged at equal intervals along the circumferential direction of the spring supporting portion 13 and the lid portion 15.

Refer to Fig. 2 as well. The spring support portion 13 includes a donut plate-shaped support portion main body 13a on which the spring Sp is mounted, and a regulation portion fixing portion 13b in which the displacement restricting portion 14 is fixed so as to project outward from the support portion main body 13a in the radial direction of the spring Sp. And have.

In the center of the support portion main body 13a, a support portion hole 13c having a circular cross section with the axis CL as the normal direction is formed through the support portion main body 13a. In other words, the spring support portion 13 has a support portion hole 13c that penetrates the spring support portion 13 along the axis CL at a position where the axis CL passes. The outer diameter of the support portion main body 13a is larger than the outer diameter of the spring Sp.

Three regulation portion fixing portions 13b are formed at equal intervals along the circumferential direction of the outer circumference of the support portion main body 13a. Each of the regulating portion fixing portions 13b has an insertion hole 13d having a circular cross section with the axis CL in the normal direction and into which the displacement regulating portion 14 is inserted. A part of the edge of the insertion hole 13d, more specifically, a portion whose distance from the axis CL is closer than the other portion of the edge is close to the outer peripheral surface of the spring Sp.

The displacement restricting portion 14 is a restricting portion main body 14a formed in a round bar shape and capable of contacting the outer peripheral surface of the spring Sp, and a portion having a small diameter formed in a part of the restricting portion main body 14a and having a lid portion 15. It has a lid fitting portion 14b that is fitted and a lid fitting portion 14b. The lid portion fitting portion 14b provided in each of the three displacement regulating portions 14 is formed so that the distance from the lower end surface of the displacement regulating portion 14 is the same.

The lid portion 15 is rotatably and detachably provided with respect to the displacement regulating portion 14. The lid portion 15 has a donut plate-shaped lid portion main body 15a that abuts on the upper surface of the spring Sp, and a claw that protrudes outward in the radial direction from the lid portion main body 15a and is fitted to the lid portion fitting portion 14b. It has a part 15b and.

At the center of the lid body 15a, a lid hole 15c having a circular cross section with the axis CL as the normal direction is formed through the lid body 15a. In other words, the lid portion 15 has a lid portion hole 15c that penetrates the lid portion 15 along the axis CL at a position where the axis CL passes.

The claw portion 15b has a substantially U shape in a plan view. Each claw portion 15b is opened in the same direction in the circumferential direction of the lid portion 15.

The spring Sp is held in a compressed state by being sandwiched between the spring support portion 13 and the lid portion 15 by the jig 10 described above. Compressive residual stress can be applied to the spring Sp by stress shot peening that projects a shot (projection material) onto the spring Sp held in a state of being compressed in the direction of the axis CL by the jig 10. Hereinafter, a detailed description will be given.

FIG. 3 shows the entire process of stress shot peening. See FIG. 4A. First, the jig 10 and the spring Sp are prepared (preparation step).

The spring Sp to be prepared is used for, for example, a front fork arranged between the vehicle body and the front wheels of a saddle-mounted vehicle, and the winding angle of the portion including the winding at both ends is changed, so that the winding angle of both ends is changed. Each roll is in contact with or in close proximity to an adjacent roll. That is, when the spring Sp is a coil spring used for a front fork, the spring Sp is a closed-end or open-end coil spring. Here, in the present invention, "the windings at both ends are close to adjacent windings" means that the gap between the windings at the ends and the windings adjacent thereto is 3 mm or less.

The free length L1, coil center diameter D, wire diameter d, and material of the spring Sp on which stress shot peening is performed are not particularly limited. For example, when the spring Sp is a coil spring used for the front fork, the spring Sp has a free length L1 of 200 to 480 mm, a coil center diameter D of 15 to 50 mm, and a wire diameter d of 3.0 to 8.0 mm. Can be exemplified.

The spring Sp may be an open-ended coil spring or a coil spring used for the rear cushion.

Next, after inserting the lower end portion of the displacement restricting portion 14 into all the supporting portion holes 13c provided in the spring supporting portion 13 arranged on an arbitrary work table, and before arranging the lid portion 15. As a result, the spring Sp is inserted from above into the portion surrounded by the displacement regulating portion 14 that is open at the top, and the spring Sp is set on the upper surface of the spring support portion 13 (coil spring setting step). Here, the length L2 from the upper surface of the spring support portion 13 to the lower end of the lid portion fitting portion 14b is set shorter than the free length L1 of the spring Sp.

Refer to FIG. 4B. Next, the lid portion 15 is pushed down to the height of the lid portion fitting portion 14b against the urging force of the spring Sp (compression step).

See FIGS. 5A and 5B. By rotating the lid portion 15 around the axis CL, the claw portion 15b is fitted to the lid portion fitting portion 14b. As a result, the spring Sp sandwiched between the spring support portion 13 and the lid portion 15 is held in a compressed state. When the claw portion 15b is fitted to the lid portion fitting portion 14b, the claw portion 15b is fitted to the lid portion fitting portion 14b having a diameter smaller than that of the regulation portion main body 14a. After the claw portion 15b is fitted to the lid portion fitting portion 14b, the movement of the lid portion 15 in the axial CL direction is restricted by the step between the regulation portion main body 14a and the lid portion fitting portion 14b.

Refer to FIG. Next, shot peening is performed on the spring Sp (shot peening step). More specifically, the metal spherical shot Sh is made to collide with the surface of the spring Sp that is rotated along the circumferential direction of the spring support portion 13 and the lid portion 15. As described above, in the jig 10, three displacement regulating portions 14 are arranged at intervals. Therefore, the shot Sh can collide not only with the outer peripheral surface of the spring Sp (the outer peripheral surface of the coil spring) but also with the inner peripheral surface of the spring Sp (the inner peripheral surface of the coil spring). As a result, compressive residual stress can be applied to the inner peripheral surface and the outer peripheral surface of the spring Sp.

For the shot Sh, any shot (projection material) that can be used for stress shot peening of the coil spring can be appropriately used. As the projection method, a centrifugal method in which the impeller Im is rotated at high speed to project the shot Sh can be adopted.

The projection conditions such as the material of the shot Sh, the average particle size, and the projection speed can be arbitrarily selected. In addition, as the projection method, an injection type can be adopted in addition to the centrifugal type.

The coil spring is manufactured through the process of performing stress shot peening on the spring Sp.

Refer to FIG. After finishing the stress shot peening, the lid portion 15 is removed from the displacement regulating portion 14, and the spring Sp surrounded by the displacement regulating portion 14 is removed (removal step).

The above is summarized below.

Refer to FIG. The jig 10 extends from the spring support portion 13 along the axis CL with reference to the spring support portion 13 on which the lower end of the spring Sp can be placed and the spring Sp supported by the spring support portion 13, and the spring Sp. A plurality of displacement regulating portions 14 that can abut on the outer peripheral surface of the spring and regulate the displacement of the spring Sp in the radial direction of the spring Sp, and the spring Sp that is supported by these displacement regulating portions 14 together with the spring supporting portion 13. It has a lid portion 15 capable of keeping the spring Sp in a compressed state by sandwiching the spring Sp.

The jig 10 has a plurality of displacement regulating portions 14 that can come into contact with the outer peripheral surface of the spring Sp. When a force in the compression direction is applied to the spring Sp, a force that escapes in the radial direction may be applied to the spring Sp. At this time, the displacement regulating unit 14 regulates the radial displacement of the spring Sp.

Refer to FIG. 6 as well. For example, shot peening may be performed while the spring Sp is held by the jig 10. At this time, since the jig 10 regulates the radial displacement of the spring Sp by the displacement regulating portion 14 arranged on the radial outside of the spring Sp, the shot Sh projected from the outside of the spring Sp is controlled. It can collide not only with the outer peripheral surface of the spring Sp but also with the inner peripheral surface. Thereby, the compressive residual stress of the inner peripheral surface and the outer peripheral surface of the spring Sp can be applied. On the other hand, unlike the jig 10, the member corresponding to the displacement regulating portion 14 (hereinafter, referred to as “displacement regulating portion of the comparative example”) is arranged inside the spring Sp in the radial direction to cure the comparative example. Consider the ingredients. In the jig of the comparative example, the shot Sh tends to collide with the displacement regulating portion of the comparative example before the shot Sh projected from the outside of the spring Sp collides with the inner peripheral surface of the spring Sp, so that the shot Sh is the spring Sp. It is hard to collide with the inner peripheral surface of. As a result, it is difficult to apply compressive residual stress to the inner peripheral surface of the spring Sp with the jig of the comparative example. In this way, by forming the displacement regulating portion 14 arranged on the outside of the spring Sp, it is possible to apply residual stress to the inner peripheral surface of the spring Sp while preventing the spring Sp from bending. The jig 10 can be provided.

In addition, only the displacement regulating portion 14 is provided between the spring supporting portion 13 and the lid portion 15. As a result, when the spring Sp is held, no other component is arranged on the inner peripheral surface of the spring Sp. With such a form, the shot Sh can be reliably collided with the inner peripheral surface of the spring Sp. As a result, it is possible to provide a jig 10 that is easier to use during shot peening.

Refer to FIGS. 1 and 5. The lid portion 15 is provided so as to be rotatable around the axis CL and has a claw portion 15b fitted to the displacement regulating portion 14, and the displacement regulating portion 14 has a lid portion 15b in a state where the claw portion 15b is fitted. It has a lid fitting portion 14b that restricts the movement of the 15 in the CL direction.

With such a form, the displacement regulating portion 14 can prevent the lid portion 15 from coming off, so that it is not necessary to use another part to prevent the lid portion 15 from coming off. Therefore, in addition to the above effects, it is possible to provide a jig 10 capable of preventing the lid portion 15 from coming off while having a small number of parts.

Refer to FIGS. 2 and 6. The spring support portion 13 has a support portion hole 13c that penetrates the spring support portion 13 along the axis CL at a position where the axis CL passes, and a member that closes the support portion hole 13c is not arranged. With such a form, the shot Sh that has passed through the support hole 13c can collide with the inner peripheral surface of the spring Sp. As a result, when the jig 10 is used for stress shot peening, it is possible to make it easier to apply compressive residual stress to the inner peripheral surface of the spring Sp. In addition, when the jig 10 is used for purposes other than stress shot peening, the workability of the spring Sp on the inner peripheral surface can be improved.

The lid portion 15 has a lid portion hole 15c that penetrates the lid portion 15 along the axis CL at a position where the axis CL passes, and a member that closes the lid portion hole 15c is not arranged. With such a form, the shot Sh that has passed through the lid hole 15c can collide with the inner peripheral surface of the spring Sp. As a result, when the jig 10 is used for stress shot peening, it is possible to make it easier to apply compressive residual stress to the inner peripheral surface of the spring Sp. In addition, when the jig 10 is used for purposes other than stress shot peening, the workability of the spring Sp on the inner peripheral surface can be improved.

In the method for manufacturing a coil spring of the present invention, a coil spring is manufactured through a step of performing shot peening on the spring Sp (stress shot peening step) while keeping the spring Sp in a compressed state using a jig 10. By going through the stress shot peening step using the jig 10, the shot peening is suppressed, and the shot peening is surely made to collide not only with the outer peripheral surface of the spring Sp but also with the inner peripheral surface of the spring Sp. Therefore, it is possible to provide a high-strength coil spring in which the body is not bent.

<Example 2>
Next, Example 2 will be described with reference to the drawings.
FIG. 8 is a diagram illustrating a method for testing a coil spring according to a second embodiment. The jig 10 shown in Example 1 can also be used when performing various tests on the spring Sp in a state where compressive stress is applied. Examples of the test in which the jig 10 can be used include a delayed fracture test, a corrosion resistance test, and a test for measuring the compressive stress applied to the spring Sp. The case where the compressive stress applied to the spring Sp is measured by using the jig 10 will be described below. For the parts common to the first embodiment, reference numerals are used and detailed description thereof will be omitted.

While keeping the spring Sp in a compressed state using the jig 10, the stress applied to the spring Sp is measured. For example, X-rays are irradiated from the irradiation unit Ir and received by the receiving unit Re. From this result, it is possible to judge that the one to which the predetermined compressive stress is applied is passed, and the one to which the predetermined compressive stress is not applied is rejected.

As the inspection method, any means such as infrared rays, porcelain distortion, laser raman, and sound elasticity can be selected in addition to the X-ray method.

As explained above, the stress applied to the spring Sp is measured while keeping the spring Sp in a compressed state using the jig 10. By using the jig 10, not only the outer peripheral surface of the spring Sp but also the inner peripheral surface can be reliably measured. Therefore, only acceptable products can be reliably provided. It can contribute to the provision of spring Sp with high commercial value.

In the above description, a jig 10 having three displacement regulating portions 14 arranged at equal intervals along the circumferential direction of the spring support portion 13 and the lid portion 15 has been illustrated, but the jig in the present invention is the same. It is not limited to the form. When the jig in the present invention has three displacement regulating portions, these displacement regulating portions may not be arranged at equal intervals along the circumferential direction of the spring support portion 13 and the lid portion 15. However, there are three displacements from the viewpoint of making it easy to suppress the bending of the spring Sp and from the viewpoint of making it easy to make the shot Sh evenly collide with the inner peripheral surface of the spring Sp when performing stress shot peening. It is preferable that the regulating portions are arranged at equal intervals along the circumferential direction of the spring supporting portion 13 and the lid portion 15.

Further, in the above description, the jig 10 having the three displacement regulating portions 14 is illustrated, but the jig in the present invention is not limited to this form. In the present invention, the number of displacement regulating portions may be a plurality. Therefore, the number of displacement regulating portions may be 2 or 4 or more. However, from the viewpoint of making it easy to suppress the bending of the spring Sp, it is preferable that the number of displacement regulating portions is 3 or more and these are arranged at equal intervals. Further, from the viewpoint of making it easy for the shot peening to evenly collide with the inner peripheral surface of the spring Sp when performing stress shot peening, it is preferable that the number of displacement regulating portions is small. Therefore, based on these, it is preferable that the jig in the present invention has three displacement regulating portions 14 arranged at equal intervals along the circumferential direction of the spring supporting portion 13 and the lid portion 15.

Further, the jig according to the present invention has been described by taking the case of holding the front fork spring as an example, but the held spring is not limited to the front fork spring of the saddle-riding vehicle. It can also be applied to springs for rear cushions and the like.

In addition, the work performed with the spring compressed can be used not only for shot peening and measurement of residual stress, but also for other purposes.

Furthermore, each embodiment can be combined as appropriate. For example, the residual stress of the coil spring after shot peening can be measured as it is by X-ray measurement.

The present invention is not limited to the examples as long as the actions and effects of the present invention are exhibited.

The jig of the present invention can be suitably used, for example, when performing stress shot peening on a coil spring.

10 ... Coil spring jig 13 ... Spring support part, 13c ... Support part hole 14 ... Displacement regulation part, 14b ... Lid part fitting part 15 ... Lid part, 15b ... Claw part, 15c ... Lid part hole Sp ... Coil spring CL ... Axis

Claims

A spring support on which one end of the coil spring can be placed,
With the coil spring supported by the spring support as a reference, it extends from the spring support along the axis of the coil spring, can come into contact with the outer peripheral surface of the coil spring, and is in the radial direction of the coil spring. A plurality of displacement regulating units that regulate the displacement of the coil spring to the
A jig for a coil spring, which is supported by these displacement regulating portions and has a lid portion capable of keeping the coil spring in a compressed state by sandwiching the coil spring together with the spring support portion.
The coil spring jig according to claim 1, wherein only the displacement regulating portion is provided between the spring supporting portion and the lid portion.
The lid portion has a claw portion that is rotatably provided about the axis and is fitted to the displacement regulating portion.
The displacement regulating portion according to claim 1 or 2, wherein the displacement regulating portion has a lid portion fitting portion that restricts the movement of the lid portion in the axial direction in a state where the claw portion is fitted. Coil spring jig.
The coil spring according to any one of claims 1 to 3, wherein the spring support portion has a support portion hole penetrating the spring support portion along the axis line at a position where the axis line passes. jig.
The coil spring jig according to any one of claims 1 to 4, wherein the lid portion has a lid portion hole penetrating the lid portion along the axis line at a position where the axis line passes. ..
A spring support portion on which one end of the coil spring can be placed and has a hole extending along the axis at a position where the axis of the coil spring passes.
A plurality of displacement regulating portions extending from the spring support portion along the axis line, being able to abut on the outer peripheral surface of the coil spring, and regulating the displacement of the coil spring in the radial direction of the coil spring.
The coil spring can be kept in a compressed state by being supported by these displacement regulating portions and rotatably provided around the axis, and by sandwiching the coil spring together with the spring supporting portion. And a lid having a hole extending along the axis at a position where the axis passes.
A claw portion provided on the lid portion and fitted to the displacement regulating portion, and a claw portion.
It has a lid fitting portion formed on the displacement regulating portion and restricting the movement of the lid portion in the axial direction in a state where the claw portion is fitted.
A jig for a coil spring in which only the displacement regulating portion is provided between the spring supporting portion and the lid portion.
A method for manufacturing a coil spring, which comprises a step of performing shot peening on the coil spring while keeping the coil spring in a compressed state using the jig for the coil spring according to any one of claims 1 to 6.
A coil spring test method in which a test is performed on the coil spring while keeping the coil spring in a compressed state using the coil spring jig according to any one of claims 1 to 6.